As it turns out, nope, they're just crazy. Here are the theories that must not be named anymore:

Ron Weasley is not a time-traveling Albus Dumbledore.

No! Not this one!

In the books, there are a number of physical descriptions and plot points that show major similarities between Dumbledore and Ron, but after a fan asked about it, Rowling confirmed they aren't the same person:

Because of their physical descriptions and some peculiar activities in the books, Draco Malfoy and Snape were thought to secretly be a werewolf and a vampire, respectively. Draco's physical changes that occur in the book are seen as the result of a werewolf curse by some, and Snape's pale complexion was viewed as evidence he was in fact undead. Unfortunately, these are not the case either:

I've never seen that one before. Draco definitely isn't a werewolf (and Snape's not a vampire). https://t.co/TSliADJvyi